This invention relates generally to telecommunications and in particular to a public network operating in conjunction with existing telecommunication lines, making it possible for callers to purchase billable communication services by means of machine-readable credit cards.
While the invention will be described mainly in connection with voice communication, it is to be understood that it is also capable of transmitting over existing telecommunication lines, facsimile images, computer data and any other form of intelligence conveyable over such lines.
A telephone system serving a multitude of parties has to take into account many factors and is therefore inherently complex. The system must be capable of rapidly setting up an exclusive channel between the calling party and any one of a large number of other located at remote points, and a ringing signal alerting the party being called. When a connection is established, the system must insure effective two-way private communication. Economics also come into play, for all of these actions must be realizable at affordable prices. Additionally, for this system to be viable for public use, it must be conveniently billable on a single call basis and it must afford universal access to call any party having a telephone facility.
In its most elementary form, a modern telephone system is composed of several central offices at different sites which are interconnected by true lines, each central office serving a large number of local telephone sets coupled to the office by loop circuits. At the central office, various switching functions are carried out automatically. Thus when the caller raises his set, and in doing so actuates a switch, his calling line must be identfied and a connection made thereto. A switching mechanism at the central office then acts to pick out an available transmission path to the called party who may be connected to the same switchboard or to some distant switchboard reached over one or more trunk lines.
The central office must also determine whether the called line is already in use and be able to signal the called station. When the parties at both ends terminate their conversation and hang up their sets, all circuits must then be restored to a state in readiness for other calls. It is also necessary to billing purposes to record the location and duration of the call.
Such central offices are established by local operating telephone companies to service a multitude of residences or business phones. Alternatively, a single business, a building complex or an otherwise defined area of high volume usage may supply its own central office function, i.e. switching equipment to service its user's calls and to link them to local operating company or other transmission lines. Thus a multitude of private telecommunication switching systems using private branch exchange (PBX) or other switching devices, have been installed in recent years to service businesses of all sizes.
A properly designed telephone system must have sufficient trunk capacity between switching points to meet the demand for services during busy periods and thereby avoid excessive delays in making a connection. Modern automatic switching mechanisms such as those used to provide the central office function to high volume business areas also provide for alternate routing to select the least expensive route and to circumvent the failure of a link in the preferred routing of a call, or when the facilities are temporarily overloaded. These switches have not heretofore been useable to carry out the central office function in a truly public application. These switches are however widely used to reduce telecommunication costs for businesses and to provide more efficient specifically applied communications for their use.
In order to introduce competition into the telephone services market, the Federal Communications Commission (FCC) recently authorized the reselling of bulk telecommunication services. Thus it is now possible for a private operator to purchase WATS or other bulk rates services from the Bell System and make them available to the public at rates below those that would have to be paid by users making calls directly through the Bell System.
WATS, or wide area telephone service, allows a customer to call anyone in one or more of the six regions into which the continental U.S. has been divided on a direct dialing basis for a flat monthly charge related to the number of regions to be called.
These FCC rulings have been construed to authorize resellers to provide telephone service to the public using switching devices as described above, which service heretofore was offered only by proprietors of telecommunication network facilities. The present invention now renders technically feasible and realizable that which the FCC has stamped as legally permissible.
The present invention is a solution to many practical problems encountered when making calls in public telephone booths of the conventional type. To illustrate a typical situation, we shall assume that a Mrs. Smith is scheduled to fly from New Yor to Chicago to visit her son, and that she has just been advised at the airport terminal that the departure of her flight has been delayed for two hours.
Since Mrs. Smith will not be able to meet her son in Chicago at the expected time, she goes to a public pay phone at the airport terminal and deposits a dime in the coin receiver. This gives her a dial tone. She then dials her son's Chicago telephone number, at which point her dime is returned and she hears the operator who instructs her to deposit two dollars and fifty cents in coins (or some such amount) for the first three minutes.
The fact that Mrs. Smith then finds that she lacks sufficient coins for this purpose should surprise no one, for this is a commonly experienced inconvenience. When Mrs. Smith finally succeeds in changing some bills to obtain the necessary coins, she must redial the number; but even then she may face a new problem. Should Mrs. Smith's call run overtime and the operator demands additional coins, she may not have them in her possession and be cut off.
We shall now replace Mrs. Smith by her husband, Mr. Smith, a businessman who is a frequent traveler and carries a Bell Telephone credit card. This card assigns Mr. Smith a 14 digit number made up of his area code and business phone number (totally 10 digits) plus 4 additional code digits. Mr. Smith need not in the same situation concern himself with a dearth of coins beyond the dime necessary to reach the operator. All he need then do is to read off to the operator his 14 digit number.
Only a relatively limited number of subscribers are in the possession of telephone company credit cards which relieve the holders of the need to deposit coins in public telephones. However, such cards are not free of practical drawbacks, for they prolong the time necessary to make a call. The caller, in addition to having to dial or key in the number of the party being called, must also supply the 14 digit credit card number.
Moreover, there is the risk that one who overhears or is otherwise informed of the 14 digit number may make unauthorized and costly long distance calls that will be billed to the card holder. The security inherent in ordinary commercial credit cards which carry a signature that can be checked and which must be presented to the seller to complete a transaction, is absent in telephone credit cards; for all one need do to make a credit call is to know the card number.
It is estimated that the five major credit card companies (Master Card, Visa, American Express, Diners and Carte Blanche) have in circulation more than 70 million credit cards. Nevertheless, the familiar statement that such cards render cash transactions obsolete is not entirely true. Though a card holder can use his card to pay for travel, lodging, food, entertainment, clothing and virtually anything else that is purchaseable, excluded from this extraordinary convenience is the ubiquitous public pay phone. Yet the public phone performs a vital function; for when away from home or office, we are all put in the position of having to use such phones to make calls.
The term "major credit cards" as used herein refers to credit cards which are nationally recognized and honored, as distinguished from those special credit cards issued by department stores and similar organizations and which are honored only by these organizations.
The term "machine-readable credit card," as used herein, is meant any card which contains identifying indicia in any form that can be magnetically, optically or otherwise scanned to generate digital signals representative of this data. Thus the existing major cards contain a magnetic stripe which when scanned yields signals identifying the nature of the card as well as the card holder's number and expiration date. However, the invention is also applicable to machine readable cards of the character-recognition type or which have magnetically embedded indicia or so-called "smart" cards which incorporate microcircuits.